1. Field of the Invention
The present invention relates to a solid oxide fuel cell.
2. Description of Related Art
Conventionally, as the material of spacers of a solid oxide fuel cell, yttrium-stabilized zirconia (hereinafter referred to as YSZ) has been used because YSZ has high electrolytic conductivity and chemical stability. As the material of interconnectors, lanthanum chromate, or a compound of lanthanum chromate and an alloy, (e.g., those with calcium, etc.) have been used. Calcium is added so as to promote sintering of lanthanum chromate.
In, in order to enhance the efficiency of power generation of a solid oxide fuel cell, the internal impedance should be lowered. As a way off lowering the internal impedance, it is known that components such as electrolytes and interconnectors in the form of green sheets are laminated and sintered together. By this method, a thin solid oxide fuel cell can be made. In this method, it is required to control both the characteristic of fine particles of the material of each green sheet and the amount of binder to be added, such that the green sheets will shrink by sintering with the same shrinkage percentage. However, during sintering, chromium and calcium diffuse from an interconnector made of lanthanum chromate to a spacer made of YSZ. Accordingly, the shrinkage percentage and the sintering characteristic of the interconnector change, and warping and separation occur between the interconnector and the spacer.